Leiodytes kualalipis Balke, Wang, Bergsten & Hendrich

Balke, Michael, Bergsten, Johannes, Wang, Liang-Jong & Hendrich, Lars, 2017, A new genus and two new species of Southeast Asian Bidessini as well as new synonyms for Oceanian species (Coleoptera, Dytiscidae), ZooKeys 647, pp. 137-151 : 140-142

Leiodytes kualalipis Balke, Wang, Bergsten & Hendrich sp. n.

Holotype.

Male (ZSM). "Malaysia, Pahang, Kuala Lipis, old rubber plantation, iv.1997, Balke & Hendrich". Paratypes, 2 males (CSR, ZSM), 1 female (CSR) "S Vietnam (Cat Tien), 120 km NNE Ho Chi Minh, Cat Tien NP, 3.-15.07.1995, A. Napolov leg."; 2 males (CWT) "Vietnam, Nam Cat Tien, 200 m, 17-25-VI-1995, leg. Malicky"; 3 males, 2 females (CWT, NHMW, TFRI). "Vietnam, Dong NAI, Nam Cat Tien NP, 120 m, 18-IX-1998, leg. L. J. Wang".

Type locality.

The type locality was around 4.200104°N 102.061570°E, altitude 100m. The entire region is now heavily transformed into oil palm plantations. The paratype locality was in Nam Cat Tien National Park, as a rough reference we obtained a position at the forest border 11.422096°N 107.427578°E.

Description.

Habitus elongate oval. Measurements: TL = 2.7 mm; TL-H = 2.4 mm; MW = 1.3 mm; elytra 4.2 × longer than pronotum.

Colouration. Beetle dark yellow with few darker basal pronotal markings and darker pattern on elytra (Fig. 3).

Surface sculpture. Head with distinct microreticulation posterior of occipital line; faint to extremely faint microreticulation along eyes and clypeus, frons without microreticulation and thus shiny / polished but with few setiferous punctures. Pronotum and elytron without microreticulation but with dense, coarse setiferous punctation. Ventral surfaces mostly polished, metaventrite, metacoxa and ventrites 1-3 with large punctures bearing short setae, distance between punctures approximately the diameter of a single puncture (similar to Leiodytes vietnamensis Wang, Satô & Yang, 1998, p. 165, Fig. 6A in their work).

Structures. Head with faint occipital line and depressed before clypeus leading to the impression that the clypeus is broadly beaded (Figs 3B, 4). Pronotum with faint lateral bead and distinct basal striae, the latter are strongly directed inwards (Figs 3B, 4). Elytron with basal striae but without sutural lines. Basal epipleural transverse carina absent. Flight wings apparently fully developed (not dissected but seen from opening caused by previous removal of the last three ventrites). Pro- and mesotarsus not conspicuously dilated laterally.

Male. Median lobe of aedeagus in lateral view thin and pointed apically, apical portion spatulate in ventral view (Figs 7A, B); lateral lobes (parameres) of two parts and distally broad, with broad “nose” or broadly twisted (Fig. 7C).

Female. Similar to male, but surface dull due to presence of strong microreticulation dorsally and ventrally (Figs 5, 6).

Diagnosis.

This is the largest species of Leiodytes and well characterised by its size as the other species in the region are distinctly smaller (below 2.2 mm or even below 2 mm long, see e.g. Régimbart 1899; Wang et al. 1998). Besides the larger size, this new species has a unique feature: the last ventrite has a deep suture apically (Fig. 6). This might be an autapomorphy for the new species.

This is, to our knowledge, the second species reported from the Malayan Peninsula, Leiodytes nicobaricus (Redtenbacher, 1867) being the other one ( Balke et al. 2004; Hendrich et al. 2004).

Etymology.

Named after the type locality, Kuala Lipis Town. The species name is a noun in apposition.

Distribution.

A species with a wide geographic range, known from the type locality in West Malaysia as well as from Southern Vietnam. The distance between these two localities is roughly 1,000 km measured as a straight line across the Gulf of Thailand.

Habitat.

The holotype was collected in shallow water, among dense layers of rotten leaves, in a shaded forest pool situated in an old rubber plantation overgrown by secondary forest (Fig. 8). The species was associated with the Dytiscidae : Copelatus sp., Hydaticus pacificus pacificus Aubé, 1838 and Hyphydrus birmanicus Régimbart, 1888.

In Vietnam, the species was collected in shallow water made by jeep on a path. Syntopically occurring dytiscid species included Leiodytes nicobaricus (Redtenbacher, 1867), Hydroglyphus orientalis (Clark, 1863) and Sandracottus maculatus (Wehncke, 1876).